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The e820 table for the kexec kernel unconditionally marks setup_data as reserved because the second kernel can reuse setup_data passed by the 1st kernel's boot loader, for example SETUP_PCI marked regions like PCI BIOS, etc. SETUP_EFI types, however, are used by kexec itself to enable EFI in the 2nd kernel. Thus, it is pointless to add this type of setup_data to the kexec e820 table as reserved. IOW, what happens is this: - 1st physical boot: no SETUP_EFI. - kexec loads a new kernel and prepares a SETUP_EFI setup_data blob, then reboots the machine. - 2nd kernel sees SETUP_EFI, reserves it both in the e820 and in the kexec e820 table. - If another kexec load is executed, it prepares a new SETUP_EFI blob and then reboots the machine into the new kernel. 5. The 3rd kexec-ed kernel has two SETUP_EFI ranges reserved. And so on... Thus skip SETUP_EFI while reserving setup_data in the e820_table_kexec table because it is not needed. [ bp: Heavily massage commit message, shorten line and improve comment. ] Signed-off-by: Dave Young <dyoung@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200212110424.GA2938@dhcp-128-65.nay.redhat.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.